This invention relates to an attachment for a spindle of a machine tool and, more particularly, to an attachment suitable for attaching to the spindle a tool provided with a tapered shank portion having a taper-size smaller than that of a corresponding tapered hole of the spindle.
A general method in prior art for fitting a tool to a spindle of a machine tool comprises the steps of inserting a tapered shank portion of the tool into a tapered hole provided for the spindle and clamping a pull-stud attached to the inserted end of the tool with a collet chuck disposed in the spindle.
In this method, when a tool provided with a tapered shank portion having a size, i.e., diameter, smaller than that of a tapered hole of the spindle is fitted to the spindle, there is used a tapered sleeve provided with a tapered member to be engaged with the tapered hole of the spindle and a tapered hole to be engaged with a tapered shank portion of the tool. The sleeve is secured to the lower end of the spindle by means of bolts to thereby fit the tool to the spindle.
However, it is required for the pull-stud of the tool to have a length considerably longer than that of a usual standard tool for clamping the pull-stud with the collet chuck of the spindle because the pull-stud has to have a length sufficient to extend through the interior of the sleeve to clamp it. In addition, it is troublesome work to secure the tapered sleeve to the lower end surface of the spindle by means of bolts. Moreover, the distance between the lower ends of the tool and the spindle is widely separated, so that the rigidity of the tool is lowered and the tool thus attached is not suitable for heavy cutting work.